1. Field of the Invention
This invention relates to cushioning devices for use in footwear, and to an article of footwear having a bellowed cushioning area.
2. Background Art
Athletic footwear must provide stable and comfortable support for the body while subject to various types of stress that occur during the various foot movements associated with athletic activity.
One of the problems associated with shoes has always been striking a balance between support and cushioning. Throughout the course of an average day, the feet and legs of an individual are subjected to substantial impact forces. Running, jumping, walking and even standing exert forces upon the feet and legs of an individual which can lead to soreness, fatigue, and injury.
Although the human foot possesses natural cushioning and rebounding characteristics, the foot alone is incapable of effectively overcoming many of the forces encountered during athletic activity. Unless an individual is wearing shoes which provide proper cushioning and support, the soreness and fatigue associated with athletic activity is more acute, and its onset accelerated. This results in discomfort for the wearer which diminishes the incentive for further athletic activity. Equally important, inadequately cushioned footwear can lead to injuries such as blisters, muscle, tendon and ligament damage, and bone stress fractures. Improper footwear can also lead to other ailments, including back pain. Thus, it is essential to have cushioning footwear when engaging in athletic activity. Further, any cushioning system added to athletic shoes must be inexpensive and simple to use.
Proper footwear should complement the natural functionality of the foot, in part by incorporating a sole which absorbs shocks and returns energy to the foot. However, different levels of cushioning may be desired depending on the type of activity. Accordingly, it is desirable to provide a shoe which can provide a varying level of support and cushioning in the sole of the foot.